Secretion of Catecholamines, Ascorbic Acid, Progesterone and Corticosterone by in-vitro Superfusion from the Adrenal of the Mongolian Gerbil (Meriones Unguiculatus): Effects of Confinement Stress

Summary

Epinephrine (E) and corticosterone (CS) levels in the superfusate of adrenals of Mongolian gerbils superfused at either 4^° or 36 ^°C rapidly declined within the first 5—20 min of superfusion. While the concentrations in superfusate of adrenals superfused at 4^°C remained very low until the end of superfusion, levels were significantly higher when adrenals were superfused at 36 ^°C. These results indicate that the amounts of E (except during the first 15—20 min of superfusion) and of CS released by adrenals superfused at 36 ^°C were due to an active, temperature- dependent release.

Confinement stress (6 hr) significantly reduced E release at 20—75 min of superfusion but had no effect on the in-vitro secretion of norepinephrine (NE) or ascorbic acid (ASA). On the other hand, the in-vitro secretion of progesterone (P) and CS was significantly increased by confinement stress at 5—120 min of superfusion. Application of this stress factor had no significant effect on adrenal content of NE, E or ASA but increased adrenal P and CS concentrations. In addition to the widely used parameters such as plasma and adrenal tissue levels, the in-vitro approach, reflecting in part the in-vivo activity of the adrenal cortex, seems very suitable to monitor changes in steroid secretion after either in-vivo or in-vitro application of ACTH. Furthermore, the effects of application of different stress factors on in-vitro secretion and possible alterations in biosynthetic pathways can be studied over several hours in the absence of central nervous system and metabolic influences.

Key words

Gerbils - catecholamines - ascorbic acid - progesterone - stress